1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly to a method of forming an interconnection for a semiconductor device using copper which is suitable for an material for interconnections of a high-integrated and high-power semiconductor device.
2. Discussion of the Background
Generally, aluminum has been widely used as a conductive material for electrical interconnection of high-integrated circuits.
However, as a width of the interconnection has become narrower, resistance of aluminum has been of some significance to delay of a resistance-capacitance time (RC time) of a circuit, and also as a dimension thereof is decreased, a design rule is limited.
Accordingly, copper has recently replaced aluminum as an interconnection material for a semiconductor device since it has specific resistance, about 40% lower than aluminum, and has excellent electromigaration. Generally, Copper is formed by a damascene process.
Now, a method of forming a copper interconnection for a conventional semiconductor device with reference to the accompanying drawings.
In FIG. 1, an insulating layer 2 is formed on a semiconductor substrate 1 in which active elements are integrated, and a groove 2a is formed in the insulating layer 2. A copper thin film 3 is formed on the insulating layer 2 including the groove 2a by a sputtering deposition method. Here, when continuously depositing copper thereon by the sputtering deposition method in order to fill up the groove 2a, a void 5 is formed in the groove 2a as shown in FIG. 2.
Next, in order to remove the void 5 in the groove 2a, the semiconductor substrate 1 on which the copper thin film 2 is deposited is put into a vacuum furnace, and annealed for more than 1 hour at 500.degree. C. or over in oxygen/hydrogen atmosphere. Thus, as shown in FIG. 3, the copper thin film 3 is flowed into the void 5 which is formed in the groove 2a, and thus the groove 2a is completely filled in without any void. Here, the above-described process is called a Cureflow process.
The conventional method of forming the copper interconnection for the semiconductor device applies the Cureflow process which requires more than 1 hour of an annealing time, and a temperature over 500.degree. C. in the oxygen/hydrogen atmosphere in order to form a conformal copper layer without any void, thus reducing productivity of the semiconductor devices.